The goals of this paper are two-fold: I wish to clarify the Aristotelian conception of the law of non-contradiction as a metaphysical rather than a semantic or logical principle, and to defend the truth of the principle in this sense. First I will explain what it in fact means that the law of non-contradiction is a metaphysical principle. The core idea is that the law of non-contradiction is a general principle derived from how things are in the world. For example, (...) there are certain constraints as to what kind of properties an object can have, and especially: some of these properties are mutually exclusive. Given this characterisation, I will advance to examine what kind of challenges the law of non-contradiction faces; the main opponent here is Graham Priest. I will consider these challenges and conclude that they do not threaten the truth of the law of non-contradiction understood as a metaphysical principle. (shrink)

A dialetheia is a sentence, A, such that both it and its negation, A, are true (we shall talk of sentences throughout this entry; but one could run the definition in terms of propositions, statements, or whatever one takes as her favourite truth bearer: this would make little difference in the context). Assuming the fairly uncontroversial view that falsity just is the truth of negation, it can equally be claimed that a dialetheia is a sentence which is both true and (...) false. (shrink)

A dialetheia is a sentence, A, such that both it and its negation, ¬A, are true (we shall talk of sentences throughout this entry; but one could run the definition in terms of propositions, statements, or whatever one takes as her favourite truth-bearer: this would make little difference in the context). Assuming the fairly uncontroversial view that falsity just is the truth of negation, it can equally be claimed that a dialetheia is a sentence which is both true and false.

En ocasiones, las paradojas involucran principios constitutivos del significado. Priest sostiene que en todos los casos deberíamos retener los principios y aceptar las contradicciones resultantes, mientras que Eklund sugiere modificar los principios en todos los casos. En este artículo, afirmo que las diferentes respuestas son adecuadas para las distintas paradojas. En particular, para paradojas del tipo del mentiroso, es mejor quedarse con el esquema T, que caracteriza el significado de “verdadero”, y aceptar las conclusiones contradictorias; mientras que para la paradoja (...) sorites, uno debería modificar la premisa problemática de Tolerancia. Finalmente, elaboro una solución para la paradoja sorites, que contiene elementos del supervaluacionismo y de la teoría de la revisión. (shrink)